A study completed by AIR and its partners looks into the use of a proactive risk assessment to identify hazards that can lead to surgical site infections in ambulatory, or outpatient, surgical centers (ASCs). The authors developed a model of risk factors, identified those that have the greatest impact on surgical site infections (SSIs), and proposed an intervention to lower the chance of infections.

Ambulatory surgery is a viable alternative to inpatient hospitalization for a range of invasive procedures. The volume and types of ambulatory surgery procedures continue to expand, providing testament to the overall safety and efficiency of surgery performed in these settings. Yet, ASCs differ in their clinical organization, structure, and processes, potentially resulting in differences in patient care outcomes.

In August 2010, the Agency for Healthcare Research and Quality (AHRQ) commissioned a study to conduct a proactive risk assessment of SSIs within the ambulatory surgery setting. AIR and its partners, Dr. Tony Slonim with Barnabas Health and Dr. Ebru Bish from the Virginia Tech College of Engineering, were selected to conduct the study, which had two primary objectives:

Using a proactive risk assessment, identify the realm of risk factors associated with SSIs resulting from procedures performed at ASCs; and

Design an intervention to mitigate the probability of SSIs for the most common risk factors for a particular set of events as identified by the proactive risk assessment.

The performance of surgery involves risk regardless of the setting, personnel, and procedure. These risks can result in surgical mishaps, ranging from infections to wrong site surgeries, and these risks increase when surgery is performed in an environment that is less regulated, more variable in its policies and procedures, and relatively understaffed. This occurs not only because the rates of known risks may be increased, but also because additional, perhaps unknown, risks resulting from a less regulated practice setting can be introduced into the performance of care.

To achieve a better understanding of how structural and process elements may affect the risk for SSIs in the ASC environment, the authors used a tool known as Socio-Technical Probabilistic Risk Assessment (ST-PRA), which incorporates risk estimates from the evidence-based literature and experiential estimates from healthcare providers. ST-PRA is particularly helpful for estimating risks in outcomes that are very rare, such as the risk of SSI in the ambulatory surgery environment, and examining single point failures as well as combinations of events that lead to the outcome of interest.

The report highlights the steps taken to build and validate the fault tree model, including data collection through a literature review, analysis of existing databases, establishment of a technical expert panel, the development of the ST-PRA fault tree models, and sensitivity analyses to determine the most important risks and combinations of risks. In addition, the report offers recommendations for possible interventions aimed at reducing the risk of SSIs. It concludes with a discussion of the study’s strengths and limitations and how the adoption of the intervention can contribute to improved patient safety.